/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package java.awt;

import java.awt.peer.TextFieldPeer;
import java.awt.event.*;
import java.util.EventListener;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
import javax.accessibility.*;


/**
 * A <code>TextField</code> object is a text component
 * that allows for the editing of a single line of text.
 * <p>
 * For example, the following image depicts a frame with four
 * text fields of varying widths. Two of these text fields
 * display the predefined text <code>"Hello"</code>.
 * <p>
 * <img src="doc-files/TextField-1.gif" alt="The preceding text describes this image."
 * style="float:center; margin: 7px 10px;">
 * <p>
 * Here is the code that produces these four text fields:
 *
 * <hr><blockquote><pre>
 * TextField tf1, tf2, tf3, tf4;
 * // a blank text field
 * tf1 = new TextField();
 * // blank field of 20 columns
 * tf2 = new TextField("", 20);
 * // predefined text displayed
 * tf3 = new TextField("Hello!");
 * // predefined text in 30 columns
 * tf4 = new TextField("Hello", 30);
 * </pre></blockquote><hr>
 * <p>
 * Every time the user types a key in the text field, one or
 * more key events are sent to the text field.  A <code>KeyEvent</code>
 * may be one of three types: keyPressed, keyReleased, or keyTyped.
 * The properties of a key event indicate which of these types
 * it is, as well as additional information about the event,
 * such as what modifiers are applied to the key event and the
 * time at which the event occurred.
 * <p>
 * The key event is passed to every <code>KeyListener</code>
 * or <code>KeyAdapter</code> object which registered to receive such
 * events using the component's <code>addKeyListener</code> method.
 * (<code>KeyAdapter</code> objects implement the
 * <code>KeyListener</code> interface.)
 * <p>
 * It is also possible to fire an <code>ActionEvent</code>.
 * If action events are enabled for the text field, they may
 * be fired by pressing the <code>Return</code> key.
 * <p>
 * The <code>TextField</code> class's <code>processEvent</code>
 * method examines the action event and passes it along to
 * <code>processActionEvent</code>. The latter method redirects the
 * event to any <code>ActionListener</code> objects that have
 * registered to receive action events generated by this
 * text field.
 *
 * @author Sami Shaio
 * @see java.awt.event.KeyEvent
 * @see java.awt.event.KeyAdapter
 * @see java.awt.event.KeyListener
 * @see java.awt.event.ActionEvent
 * @see java.awt.Component#addKeyListener
 * @see java.awt.TextField#processEvent
 * @see java.awt.TextField#processActionEvent
 * @see java.awt.TextField#addActionListener
 * @since JDK1.0
 */
public class TextField extends TextComponent {

  /**
   * The number of columns in the text field.
   * A column is an approximate average character
   * width that is platform-dependent.
   * Guaranteed to be non-negative.
   *
   * @serial
   * @see #setColumns(int)
   * @see #getColumns()
   */
  int columns;

  /**
   * The echo character, which is used when
   * the user wishes to disguise the characters
   * typed into the text field.
   * The disguises are removed if echoChar = <code>0</code>.
   *
   * @serial
   * @see #getEchoChar()
   * @see #setEchoChar(char)
   * @see #echoCharIsSet()
   */
  char echoChar;

  transient ActionListener actionListener;

  private static final String base = "textfield";
  private static int nameCounter = 0;

  /*
   * JDK 1.1 serialVersionUID
   */
  private static final long serialVersionUID = -2966288784432217853L;

  /**
   * Initialize JNI field and method ids
   */
  private static native void initIDs();

  static {
        /* ensure that the necessary native libraries are loaded */
    Toolkit.loadLibraries();
    if (!GraphicsEnvironment.isHeadless()) {
      initIDs();
    }
  }

  /**
   * Constructs a new text field.
   *
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  public TextField() throws HeadlessException {
    this("", 0);
  }

  /**
   * Constructs a new text field initialized with the specified text.
   *
   * @param text the text to be displayed. If <code>text</code> is <code>null</code>, the empty
   * string <code>""</code> will be displayed.
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  public TextField(String text) throws HeadlessException {
    this(text, (text != null) ? text.length() : 0);
  }

  /**
   * Constructs a new empty text field with the specified number
   * of columns.  A column is an approximate average character
   * width that is platform-dependent.
   *
   * @param columns the number of columns.  If <code>columns</code> is less than <code>0</code>,
   * <code>columns</code> is set to <code>0</code>.
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  public TextField(int columns) throws HeadlessException {
    this("", columns);
  }

  /**
   * Constructs a new text field initialized with the specified text
   * to be displayed, and wide enough to hold the specified
   * number of columns. A column is an approximate average character
   * width that is platform-dependent.
   *
   * @param text the text to be displayed. If <code>text</code> is <code>null</code>, the empty
   * string <code>""</code> will be displayed.
   * @param columns the number of columns.  If <code>columns</code> is less than <code>0</code>,
   * <code>columns</code> is set to <code>0</code>.
   * @throws HeadlessException if GraphicsEnvironment.isHeadless() returns true.
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  public TextField(String text, int columns) throws HeadlessException {
    super(text);
    this.columns = (columns >= 0) ? columns : 0;
  }

  /**
   * Construct a name for this component.  Called by getName() when the
   * name is null.
   */
  String constructComponentName() {
    synchronized (TextField.class) {
      return base + nameCounter++;
    }
  }

  /**
   * Creates the TextField's peer.  The peer allows us to modify the
   * appearance of the TextField without changing its functionality.
   */
  public void addNotify() {
    synchronized (getTreeLock()) {
      if (peer == null) {
        peer = getToolkit().createTextField(this);
      }
      super.addNotify();
    }
  }

  /**
   * Gets the character that is to be used for echoing.
   * <p>
   * An echo character is useful for text fields where
   * user input should not be echoed to the screen, as in
   * the case of a text field for entering a password.
   * If <code>echoChar</code> = <code>0</code>, user
   * input is echoed to the screen unchanged.
   * <p>
   * A Java platform implementation may support only a limited,
   * non-empty set of echo characters. This function returns the
   * echo character originally requested via setEchoChar(). The echo
   * character actually used by the TextField implementation might be
   * different.
   *
   * @return the echo character for this text field.
   * @see java.awt.TextField#echoCharIsSet
   * @see java.awt.TextField#setEchoChar
   */
  public char getEchoChar() {
    return echoChar;
  }

  /**
   * Sets the echo character for this text field.
   * <p>
   * An echo character is useful for text fields where
   * user input should not be echoed to the screen, as in
   * the case of a text field for entering a password.
   * Setting <code>echoChar</code> = <code>0</code> allows
   * user input to be echoed to the screen again.
   * <p>
   * A Java platform implementation may support only a limited,
   * non-empty set of echo characters. Attempts to set an
   * unsupported echo character will cause the default echo
   * character to be used instead. Subsequent calls to getEchoChar()
   * will return the echo character originally requested. This might
   * or might not be identical to the echo character actually
   * used by the TextField implementation.
   *
   * @param c the echo character for this text field.
   * @see java.awt.TextField#echoCharIsSet
   * @see java.awt.TextField#getEchoChar
   * @since JDK1.1
   */
  public void setEchoChar(char c) {
    setEchoCharacter(c);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>setEchoChar(char)</code>.
   */
  @Deprecated
  public synchronized void setEchoCharacter(char c) {
    if (echoChar != c) {
      echoChar = c;
      TextFieldPeer peer = (TextFieldPeer) this.peer;
      if (peer != null) {
        peer.setEchoChar(c);
      }
    }
  }

  /**
   * Sets the text that is presented by this
   * text component to be the specified text.
   *
   * @param t the new text.
   * @see java.awt.TextComponent#getText
   */
  public void setText(String t) {
    super.setText(t);

    // This could change the preferred size of the Component.
    invalidateIfValid();
  }

  /**
   * Indicates whether or not this text field has a
   * character set for echoing.
   * <p>
   * An echo character is useful for text fields where
   * user input should not be echoed to the screen, as in
   * the case of a text field for entering a password.
   *
   * @return <code>true</code> if this text field has a character set for echoing;
   * <code>false</code> otherwise.
   * @see java.awt.TextField#setEchoChar
   * @see java.awt.TextField#getEchoChar
   */
  public boolean echoCharIsSet() {
    return echoChar != 0;
  }

  /**
   * Gets the number of columns in this text field. A column is an
   * approximate average character width that is platform-dependent.
   *
   * @return the number of columns.
   * @see java.awt.TextField#setColumns
   * @since JDK1.1
   */
  public int getColumns() {
    return columns;
  }

  /**
   * Sets the number of columns in this text field. A column is an
   * approximate average character width that is platform-dependent.
   *
   * @param columns the number of columns.
   * @throws IllegalArgumentException if the value supplied for <code>columns</code> is less than
   * <code>0</code>.
   * @see java.awt.TextField#getColumns
   * @since JDK1.1
   */
  public void setColumns(int columns) {
    int oldVal;
    synchronized (this) {
      oldVal = this.columns;
      if (columns < 0) {
        throw new IllegalArgumentException("columns less than zero.");
      }
      if (columns != oldVal) {
        this.columns = columns;
      }
    }

    if (columns != oldVal) {
      invalidate();
    }
  }

  /**
   * Gets the preferred size of this text field
   * with the specified number of columns.
   *
   * @param columns the number of columns in this text field.
   * @return the preferred dimensions for displaying this text field.
   * @since JDK1.1
   */
  public Dimension getPreferredSize(int columns) {
    return preferredSize(columns);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getPreferredSize(int)</code>.
   */
  @Deprecated
  public Dimension preferredSize(int columns) {
    synchronized (getTreeLock()) {
      TextFieldPeer peer = (TextFieldPeer) this.peer;
      return (peer != null) ?
          peer.getPreferredSize(columns) :
          super.preferredSize();
    }
  }

  /**
   * Gets the preferred size of this text field.
   *
   * @return the preferred dimensions for displaying this text field.
   * @since JDK1.1
   */
  public Dimension getPreferredSize() {
    return preferredSize();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getPreferredSize()</code>.
   */
  @Deprecated
  public Dimension preferredSize() {
    synchronized (getTreeLock()) {
      return (columns > 0) ?
          preferredSize(columns) :
          super.preferredSize();
    }
  }

  /**
   * Gets the minimum dimensions for a text field with
   * the specified number of columns.
   *
   * @param columns the number of columns in this text field.
   * @since JDK1.1
   */
  public Dimension getMinimumSize(int columns) {
    return minimumSize(columns);
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getMinimumSize(int)</code>.
   */
  @Deprecated
  public Dimension minimumSize(int columns) {
    synchronized (getTreeLock()) {
      TextFieldPeer peer = (TextFieldPeer) this.peer;
      return (peer != null) ?
          peer.getMinimumSize(columns) :
          super.minimumSize();
    }
  }

  /**
   * Gets the minimum dimensions for this text field.
   *
   * @return the minimum dimensions for displaying this text field.
   * @since JDK1.1
   */
  public Dimension getMinimumSize() {
    return minimumSize();
  }

  /**
   * @deprecated As of JDK version 1.1, replaced by <code>getMinimumSize()</code>.
   */
  @Deprecated
  public Dimension minimumSize() {
    synchronized (getTreeLock()) {
      return (columns > 0) ?
          minimumSize(columns) :
          super.minimumSize();
    }
  }

  /**
   * Adds the specified action listener to receive
   * action events from this text field.
   * If l is null, no exception is thrown and no action is performed.
   * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
   * >AWT Threading Issues</a> for details on AWT's threading model.
   *
   * @param l the action listener.
   * @see #removeActionListener
   * @see #getActionListeners
   * @see java.awt.event.ActionListener
   * @since JDK1.1
   */
  public synchronized void addActionListener(ActionListener l) {
    if (l == null) {
      return;
    }
    actionListener = AWTEventMulticaster.add(actionListener, l);
    newEventsOnly = true;
  }

  /**
   * Removes the specified action listener so that it no longer
   * receives action events from this text field.
   * If l is null, no exception is thrown and no action is performed.
   * <p>Refer to <a href="doc-files/AWTThreadIssues.html#ListenersThreads"
   * >AWT Threading Issues</a> for details on AWT's threading model.
   *
   * @param l the action listener.
   * @see #addActionListener
   * @see #getActionListeners
   * @see java.awt.event.ActionListener
   * @since JDK1.1
   */
  public synchronized void removeActionListener(ActionListener l) {
    if (l == null) {
      return;
    }
    actionListener = AWTEventMulticaster.remove(actionListener, l);
  }

  /**
   * Returns an array of all the action listeners
   * registered on this textfield.
   *
   * @return all of this textfield's <code>ActionListener</code>s or an empty array if no action
   * listeners are currently registered
   * @see #addActionListener
   * @see #removeActionListener
   * @see java.awt.event.ActionListener
   * @since 1.4
   */
  public synchronized ActionListener[] getActionListeners() {
    return getListeners(ActionListener.class);
  }

  /**
   * Returns an array of all the objects currently registered
   * as <code><em>Foo</em>Listener</code>s
   * upon this <code>TextField</code>.
   * <code><em>Foo</em>Listener</code>s are registered using the
   * <code>add<em>Foo</em>Listener</code> method.
   *
   * <p>
   * You can specify the <code>listenerType</code> argument
   * with a class literal, such as
   * <code><em>Foo</em>Listener.class</code>.
   * For example, you can query a
   * <code>TextField</code> <code>t</code>
   * for its action listeners with the following code:
   *
   * <pre>ActionListener[] als = (ActionListener[])(t.getListeners(ActionListener.class));</pre>
   *
   * If no such listeners exist, this method returns an empty array.
   *
   * @param listenerType the type of listeners requested; this parameter should specify an interface
   * that descends from <code>java.util.EventListener</code>
   * @return an array of all objects registered as <code><em>Foo</em>Listener</code>s on this
   * textfield, or an empty array if no such listeners have been added
   * @throws ClassCastException if <code>listenerType</code> doesn't specify a class or interface
   * that implements <code>java.util.EventListener</code>
   * @see #getActionListeners
   * @since 1.3
   */
  public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
    EventListener l = null;
    if (listenerType == ActionListener.class) {
      l = actionListener;
    } else {
      return super.getListeners(listenerType);
    }
    return AWTEventMulticaster.getListeners(l, listenerType);
  }

  // REMIND: remove when filtering is done at lower level
  boolean eventEnabled(AWTEvent e) {
    if (e.id == ActionEvent.ACTION_PERFORMED) {
      if ((eventMask & AWTEvent.ACTION_EVENT_MASK) != 0 ||
          actionListener != null) {
        return true;
      }
      return false;
    }
    return super.eventEnabled(e);
  }

  /**
   * Processes events on this text field. If the event
   * is an instance of <code>ActionEvent</code>,
   * it invokes the <code>processActionEvent</code>
   * method. Otherwise, it invokes <code>processEvent</code>
   * on the superclass.
   * <p>Note that if the event parameter is <code>null</code>
   * the behavior is unspecified and may result in an
   * exception.
   *
   * @param e the event
   * @see java.awt.event.ActionEvent
   * @see java.awt.TextField#processActionEvent
   * @since JDK1.1
   */
  protected void processEvent(AWTEvent e) {
    if (e instanceof ActionEvent) {
      processActionEvent((ActionEvent) e);
      return;
    }
    super.processEvent(e);
  }

  /**
   * Processes action events occurring on this text field by
   * dispatching them to any registered
   * <code>ActionListener</code> objects.
   * <p>
   * This method is not called unless action events are
   * enabled for this component. Action events are enabled
   * when one of the following occurs:
   * <ul>
   * <li>An <code>ActionListener</code> object is registered
   * via <code>addActionListener</code>.
   * <li>Action events are enabled via <code>enableEvents</code>.
   * </ul>
   * <p>Note that if the event parameter is <code>null</code>
   * the behavior is unspecified and may result in an
   * exception.
   *
   * @param e the action event
   * @see java.awt.event.ActionListener
   * @see java.awt.TextField#addActionListener
   * @see java.awt.Component#enableEvents
   * @since JDK1.1
   */
  protected void processActionEvent(ActionEvent e) {
    ActionListener listener = actionListener;
    if (listener != null) {
      listener.actionPerformed(e);
    }
  }

  /**
   * Returns a string representing the state of this <code>TextField</code>.
   * This method is intended to be used only for debugging purposes, and the
   * content and format of the returned string may vary between
   * implementations. The returned string may be empty but may not be
   * <code>null</code>.
   *
   * @return the parameter string of this text field
   */
  protected String paramString() {
    String str = super.paramString();
    if (echoChar != 0) {
      str += ",echo=" + echoChar;
    }
    return str;
  }


    /*
     * Serialization support.
     */
  /**
   * The textField Serialized Data Version.
   *
   * @serial
   */
  private int textFieldSerializedDataVersion = 1;

  /**
   * Writes default serializable fields to stream.  Writes
   * a list of serializable ActionListener(s) as optional data.
   * The non-serializable ActionListener(s) are detected and
   * no attempt is made to serialize them.
   *
   * @serialData Null terminated sequence of zero or more pairs. A pair consists of a String and
   * Object. The String indicates the type of object and is one of the following : ActionListenerK
   * indicating and ActionListener object.
   * @see AWTEventMulticaster#save(ObjectOutputStream, String, EventListener)
   * @see java.awt.Component#actionListenerK
   */
  private void writeObject(ObjectOutputStream s)
      throws IOException {
    s.defaultWriteObject();

    AWTEventMulticaster.save(s, actionListenerK, actionListener);
    s.writeObject(null);
  }

  /**
   * Read the ObjectInputStream and if it isn't null,
   * add a listener to receive action events fired by the
   * TextField.  Unrecognized keys or values will be
   * ignored.
   *
   * @throws HeadlessException if <code>GraphicsEnvironment.isHeadless()</code> returns
   * <code>true</code>
   * @see #removeActionListener(ActionListener)
   * @see #addActionListener(ActionListener)
   * @see java.awt.GraphicsEnvironment#isHeadless
   */
  private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException, HeadlessException {
    // HeadlessException will be thrown by TextComponent's readObject
    s.defaultReadObject();

    // Make sure the state we just read in for columns has legal values
    if (columns < 0) {
      columns = 0;
    }

    // Read in listeners, if any
    Object keyOrNull;
    while (null != (keyOrNull = s.readObject())) {
      String key = ((String) keyOrNull).intern();

      if (actionListenerK == key) {
        addActionListener((ActionListener) (s.readObject()));
      } else {
        // skip value for unrecognized key
        s.readObject();
      }
    }
  }

/////////////////
// Accessibility support
////////////////


  /**
   * Gets the AccessibleContext associated with this TextField.
   * For text fields, the AccessibleContext takes the form of an
   * AccessibleAWTTextField.
   * A new AccessibleAWTTextField instance is created if necessary.
   *
   * @return an AccessibleAWTTextField that serves as the AccessibleContext of this TextField
   * @since 1.3
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleAWTTextField();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>TextField</code> class.  It provides an implementation of the
   * Java Accessibility API appropriate to text field user-interface elements.
   *
   * @since 1.3
   */
  protected class AccessibleAWTTextField extends AccessibleAWTTextComponent {

    /*
     * JDK 1.3 serialVersionUID
     */
    private static final long serialVersionUID = 6219164359235943158L;

    /**
     * Gets the state set of this object.
     *
     * @return an instance of AccessibleStateSet describing the states of the object
     * @see AccessibleState
     */
    public AccessibleStateSet getAccessibleStateSet() {
      AccessibleStateSet states = super.getAccessibleStateSet();
      states.add(AccessibleState.SINGLE_LINE);
      return states;
    }
  }

}
